THE big rally in the oil price in recent weeks is down to Chinese stockpiling, a leading energy industry analyst has claimed.

Oil industry experts Bernstein Research say they have been spying on the world's third-largest economy and have concluded China is actively hoarding supplies.

After the spectacular crash in the crude price last year following an all-time high of $147 a barrel, oil has soared again this year, up 70% since mid-January. In the past four weeks, the oil price has jumped 25% to trade around the $60-a-barrel level again.

Energy analysts have been scratching their heads for a reason, other than the recent dollar weakness which always pushes up the value of crude.

Analysts have argued that global demand remains weak, the Saudi-led cartel of major oil producers Opec has not cut production as deeply as it might and output from non-Opec countries is robust.

But according to Bernstein's Neil McMahon: "If the supply/demand balance is not driving higher oil prices, then what is?

"We believe that increased imports into China could be part of the explanation.

McMahon says Chinese imports spiked in March and April and the country's storage levels have reached a new peak.

"We believe [the rise in the oil price] reflects not strengthening demand, but rather China's efforts to boost its strategic petroleum reserve," he said. "To verify this we have utilised satellite tracking of tanker movements, as well as time-lapse satellite images to observe the amount of storage expansion.

"Our analysis confirms that tanker capacity arrivals into China have spiked up in recent months, in line with imports, but more importantly, tanker arrivals into the ports [holding strategic reserves] have increased materially.

"Satellite images confirm a significant increase in storage construction in the last few years. This suggests that China is stockpiling crude oil.

"This recent drive by the Chinese to fill their reserves should have offered some support to crude prices and will continue to do so going forward."